OutputType

DreamShader » Builtins » OutputType

The argument with which a 1.x call said what kind of value a reflected builtin produces. Since 2.0.0 the builtin catalog says it for every class, and OutputType keeps two jobs: the output type of a Custom node, and a width hint in a 1.x source.

Synopsis

{ OutputType | ResultType } = <type-token>

The legacy front end finds OutputType and ResultType ignoring case and takes them off the call before the binder sees it — on a Custom call it keeps the first of them as the node's output type and drops a second. Neither is ever bound as a pin or property. The token may be quoted or bare: OutputType = "float3" and OutputType = float3 are identical.

It is required nowhere (since 2.0.0; 1.x required it on every generic call and on a property declaration outside its table). A .dss has no such argument: a reflected node is called as UE.<ClassShortName>(Pin = …, Property = …) and its value is typed by the catalog.

Where it is read

A token that fits none of these — a texture, MaterialAttributes, Substrate or SamplerState token on a non-Custom call, a matrix, a misspelling — is dropped without a diagnostic (since 2.0.0; 1.x reported an unsupported token), and the catalog types the value.

[!NOTE] The width hint follows 1.x where the catalog would build another graph: float Cam = UE.Expression(Class = "CameraPositionWS", OutputType = "float") types Cam as a float and connects the node's whole output wherever Cam is read, which is what the 1.x graph did. On a node the engine types the same way the hint does, it changes nothing.

Accepted tokens

On a Custom node

Compared ignoring case and with every space removed. Anything else is DSH5261.

(since 2.0.0) int, uint, bool and their vectors, ivec*, uvec*, bvec*, the texture tokens, StaticBool and Substrate are DSH5261 here. A bare MaterialAttributes is read as the type material and is DSH5261 as well; quote it.

On any other call, and on a property declaration

A token is a 1.x type spelling, compared ignoring case:

On a Graph call the token is trimmed but keeps its inner spaces (" float 4 " is no token); on a property declaration every space is removed first. Underscores and dashes are never removed: float_4 and Material-Attributes are not spellings.

Output mask pseudo-names

Distinct from OutputType: the Output / OutputName argument selects which output of a multi-output node is read, and becomes .Name on the call. The name is one of the outputs the catalog lists for the class. An output the engine leaves unnamed is listed under the channels of its mask — R, G, B, A, RG, RGB, RGBA — when the class has more than one output, unless the class already uses that name. A single output keeps the empty name and is the value of the call.

The name is compared exactly; in a 1.x source a name that matches only ignoring case is accepted with DSH5276. A name no output has is DSH5201 (since 2.0.0; 1.x tested the seven mask names against every unnamed output, in a fixed order). On a node whose outputs are all channel views of one value, a swizzle inside one output is that output (UE.VertexColor().a). Full rules: UE.Expression.

[!NOTE] These are not OutputType values, and an OutputType token is never a valid Output selector. UE.Expression(Class = "BreakMaterialAttributes", Output = "BaseColor") selects by output name; UE.VertexColor(Output = "RGB") selects the output its mask names.

Notes

• The width comes from the catalog. UE.Expression(Class = "WorldPosition") is a node whose first output, XYZ, is a float3; no token is needed or consulted for that. See Result type and component count.
• Two calls that differ only in how OutputType is spelled — float3 against vec3 — are one node: the IR merges nodes, not spellings (since 2.0.0). See Node reuse.
• This token set is the 1.x type vocabulary. The Properties section additionally accepts the parameter-node tokens; see Types, Compact types and Inputs / Outputs / Results.

Diagnostics

Every code is described on its page in Diagnostics.

Example

Shader(Name="Docs/M_OutputTypes")
{
    Properties {
        // Declaration surface: the type of the local `Radius`.
        UE.Expression(Class = "ObjectRadius", OutputType = "float1") Radius;
    }

    Settings { ShadingModel = "Unlit"; }

    Outputs {
        vec3 Color;
        Base.EmissiveColor = Color;
    }

    Graph {
        // Not needed: the catalog gives TextureCoordinate a float2.
        float2 uv = UE.Expression(Class = "TextureCoordinate", OutputType = "float2");

        // ResultType is the alias.
        float t = UE.Expression(Class = "Time", ResultType = "float1");

        // The node's own output type on a Custom node.
        float3 tinted = UE.Expression(Class = "Custom", OutputType = "float3",
                                      Code = "return In * 0.5f;", In = vec3(uv.x, uv.y, t));

        // An output the catalog names after its mask.
        float3 vcol = UE.Expression(Class = "VertexColor", Output = "RGB");

        Color = tinted * vcol * Radius;
    }
}

See also

• UE.Expression — the call form this argument belongs to
• UE.* catalogue — the 1.x names, which drop this argument
• Builtins — the call surfaces
• Substrate — where the argument is dropped
• Types — the language's declaration type tokens
• Compact types — the parameter type tokens
• Inputs / Outputs / Results — the function parameter type set
• Conversions — widths and how values fit
• Node reuse — identical nodes
• Diagnostics index — every code